Introduction

PHP is a server scripting language, and It is a powerful tool for making interactive and dynamic Web-pages. I have used WampServer 2.2 for following excercise..

<?php
function sum_of_digits($nums) {
    $digits_sum = 0;
      for ($i = 0; $i < strlen($nums); $i++) {
             $digits_sum += $nums[$i];
               }
      return $digits_sum;
}
echo sum_of_digits("123456789")."<br>";
echo sum_of_digits("999999")."<br>";
?>

Result